Preparation of plates for printing by greasy ink



Patented Sept. 9, 1924.

- MARIANO Di: SPERATI, OF TURIN, ITALY.

PREPARATION OF PIiATES FOB- PRINTING BY GY INK.

No Drawing.

To all whom it may concern: v

Be it known that I, MARIANO D1 1 SPERATI,

a subject of the King of. Italy, residing at Turin, Italy, have invented certain new and useful Improvements in the Preparation of Plates for Printing by Greasy Ink, of

which the following is a specification.

The present invention relates to the production of plates for printing with greasy 10 ink, and has for its object a treatment supplemental to the methods for production of said plates of the kind disclosed in' my prior Patent N o. l,433,806,'dated October 31, 1922.

In my said patent is disclosed a method of producing plates for printing with greasy ink, consisting in exposing, developing and fixing a gelatino-silver haloid sensitized layer to obtain an image thereon, intensifying the image, sensitizing said layer by a bath of an alkali bichromate, exposing the layer to light from the back to render insoluble the bichromated gelatin in the zones acted on bythe light during such exposure and Washing said layer.

My patent also discloses the roduction of the above stated intensificatlon of the image by treating the plate with mercuric chlorid and then with ammonia to partly replace the metallic silver of the image by a mercurous compound. I

Now the present invention has for its object a method supplemental to the methods of the kind above referred to, and comprising a treatment by which a clear colour,

probably white or some light colour such as gray or yellow, is imparted to the printing layer, and the same layer is made more compact and hard.

When the. printing layer of the plates has such a .white or clear colour the advantage is obtained that the ink put on it during the inking operation is visible to the operator and therefore the same operator is enabled to carefully control such inking operation and stop it when the desired half tone effect is reached; further the increased hardness imparted to the. layer makes it possible to obtain from a plate a larger number of prints than heretofore.

According to the present invention the negative, after a treatment of the kind described in my said patent, is treated with a solution adapted to convert the salts of Application filed November 2, 1922. Serial No. 598,878.

silver or mercury into a compound having a white. or light colour.-

A number of substances may be used for this purpose, such as potassium ferricyanid and other substances adapted to act in the above stated manner on the metal salts present in the layer, but inthe preferred embodimentof this invention the negative is treated with a solution of potassium iodid (KI) and iodin (I), this solution havin preferably the following composition: lodin (I) gr. 1.5; potassium iodid (KI) gr. 5; distilled water gr. 100.

By reason of this treatment the metal providing the image in the layer is converted into an iodin salt of the same metal, and therefore are obtained in suspension in the gelatin, grains of silver iodid (AgI) or rains of mercurous iodid (HgI) when an mtensification of the negative has been obtained by the treatment with mercuric chlorid and ammonia, as above referred to.

In the first case the surface of the layer is made white, the silver iodid (AgI) being white; in the second case the colour of the layer is yellow like the mercurous iodid (HgI).

In both cases the plate surface 1s rendered a clear or light colour and this enables the operator to easily and accurately inspect and control the inking operation.

Further by the described treatment in the layer of gelatin are produced larger and heavier grains which impart a high compactness to the elatin layer, this layer being made more ard because of the compression produced in it by the increase in size of the grains in suspension therein.

The same result is thus obtained as by means of the known gelatin hardeners (as chromium salts, formic aldehyde, tannic acid, and the like) with the difference that the last named compounds by their specific action 'make the gelatin unsuitable. for photocollographic use; on the contrary it has been found that the gelatin is improved by the treatment accordmg to the present invention.

What vI claim as my invention and desire to secure by United States Letters Patent is 1. A method of producing plates for printing with greasy ink, consisting in exposing, developing and fixing a gelatinoposing, developin silver haloid sensitized layer to obtain an image thereon, sensitizing said layer by a bath of an alkali bichromate, exposing the layer to light from the back to render insoluble the bichromated gelatin in the zones acted on by the light during such exposure, washing said layer and treating it with a substance adapted to convert the silver contained in said image into a compound having a light colour.

2. A method of producing plates for printing with greasy ink, consisting in exposing, developin and fixing a gelatinosilver haloid sensltized layer to obtain an image thereon, sensitizing said layer by a bath of an alkali bichromate, exposing the la er to light from the back to render insoluble the bichromated gelatin in the zones acted on by the light during such exposure, washing said layer and treating it with a solution containing iodin.

3. A method of producing plates for printing with greasy ink, consisting in exposing developin and fixing a gelatinosilver haloid sensitized layer to obtain an image thereon, sensitizing said layer by a bath of an alkali bichromate, exposing said layer to light from the back to render the bichromated gelatin insoluble in the zones acted on by the light during such exposure, washing said layer and treating it with a solution of iodin in potassium iodid.

d. A method of producing plates for printing with greasy ink, consisting in exposing, developin and fixing a elatinosilver haloid sensitized layer to o tain an image thereon, sensitizing said layer by a bath of an alkali bichromate, exposing said la er to light from the back to render inso uble the bichromated gelatin in the zones acted on by the light during such exposure, washing said layer and treating it with a solution consisting substantially of iodin gr.

' 1,5; potassium iodid gr. 5 and distilled water gr. 100.

;5, A method of producing plates for printing with greasy ink, consisting in exposing, developin and fixing a elatinosilver haloid sensitized layer to o tain an image thegeon, intensifying said image, sensitizingsaid layer by a bath of an alkali b1chromate, exposing the layer to li ht from the back to render the bichromated gelatin insoluble in the zones acted on by the light during such exposure, washing saidlayer and treating it with a substance ada ted to convert thepom ound producing sai image into a compbu'n having a light colour.

6. A method of producing plates for,

printing with greasyink, consisting in exand fixing a elatinosilver haloid sensitized layer to o tain an image thereon, intensifying the image, sensitizing said layer by a bath or an alkalibichromate, exposing the layer to light from the back to render the bichromated gelatin insoluble in the zones acted on by the light during such exposure, washing said layer and treating it with a solution containing iodin.

7. A method of producing plates for printing with greasy ink, consisting in exposing, developing and fixing a gelatinosilver haloid sensitized layer to obtain an image thereon, intensifying the image, sensitizing said layer by a bath of an alkali bichromate, exposing the layer to light from the back to render the bichromated gelatin insoluble in the zones acted on by the light during such exposure, washing said layer and treating it with a solution of iodin in potassium iodid.

8. A method of producing plates for printing with greasy ink, consisting in exposing, developin and fixing a gelatinosilver haloid sensitized layer to obtain an image thereon, intensifying the image, sensitizing said layer by a bath of an alkali bichromate, exposing the layer to light from the back to render insoluble the bichromated elatin in the zones acted on by the light during such exposure, washing said layer. and treating-it with a solution consisting substantially of iodin gr. 1.5; potassium iodid gr. 5 and distilled water gr. 100.

9. A method of producing plates for printing with greasy ink, consisting in exposing, developing and fixing a gelatinosilver haloid sensitized layer to obtain an image thereon, treating said layer with mercuric chlorid and then with ammonia to partly replace the metallic silver oi the image b a mercurous compound, sensitizing sai layer by a bath of an alkali bichromate, exposing the layer to light from the back to render insoluble the bichromated gelatin in the zones acted on by the light during. such exposure, washing said layer and treating it with a substance adapted to convert the silver and mercury contained in the image into a compound having a light colour.

10. A method of producing plates for printing with greasy ink, consisting in exposing, developin and fixing a gelatinosilver haloid sensitized layer to obtain an image thereon, treatin said layer with mercuric chlorid and t en with ammonia to partly replace the metallic silver oi the image by a mercurous compound, sensitizing said layer by a bath of an alkali bichromate, exposing the layer to light from the back to render insoluble the bichromated gelatin in. the zones acted on by the light during such exposure, washing said layer anatlil treating it with a solution containing 1c in.

11. A method of producing plates for printing with greasy ink, consisting in exposing, developing and fixing a gelatino- Mill lltl

aeoepee silver haloid sensitized layer to obtain an image thereon, treatin said layer with mercuric chlorid and t en with ammonia to partly replace the metallic silver of the image by a mercurous compound, sensitizing said layer by a bath of an alkali bichromate, exposing the layer to light from the back to render insoluble the bichromated gelatin in the zones acted on by the light during such exposure, washing said layer and treating itwith a solution containing iodin in potassium iodid.

12. A method of roducing plates fon printing with greasy ink, conslsting in exposing developin and fixing a elatinosilver haloid sensitized layer to obtain an image thereon, treating said layer with mercuric chlorid and then with ammonia to partly replace the metallic silver: of the image by a mercurous compound, sensitizing said layer by a bath of an alkali bichromate; exposing the layer to light from the back to render insoluble the bichromated gelatin in the zones acted on by the light uring' such exposure, washing said layer and treating it with a solution consisting substantially of iodin gr. 1.5; potassium iodid gr. 5 and distilled water 100.

In testimony whereof I a 1: my ,signature.-

MARIANO ma SPERATI. 

